1. Field of the Invention
This invention relates to a pipe coupling apparatus which is useful for making connection to a pipe or which, when used in pairs, can be used to join two pieces of pipe or the like. More particularly, this invention relates to a pipe coupling apparatus which is particularly useful for making underwater pipe connections and which can be operated remotely by the use of hydraulic fluids.
2. Description of the Prior Art
Most prior art pipe coupling devices either had hydraulically actuated seal means for effecting a seal between a coupling and a pipe without any gripping means or had gripping means for effecting locking of the coupling with the pipe without any seal means. Subsequent to that, there developed a type of pipe coupling which was hydraulically actuated which combined both seal means and gripping means which were hydraulically actuated, but which actuation was by the same system. The following U.S. patents are generally illustrative of this type of apparatus, and they include U.S. Pat. Nos. 3,393,926, 3,704,033 and 3,830,526. Couplings of the type taught in these patents have been very useful in certain installations and have been considered superior to certain prior art couplings. However, they are not suitable in all installations and all working conditions, and there developed a need for an improved underwater hydraulically actuated pipe coupling in which the seal means could be separately actuated from the gripping means and wherein the two could be separately actuated and operated to accommodate variations in size, pipeline pressures and external environmental conditions.